It’s quite small. About 1100 full-time residents and another similar amount 4 miles down the road in Black Lake. It’s like a spread out “over 55 community”, but with high speed fiber, the ski resort, mountain biking and PGA course younger people who can work remotely are trickling in. A good thing.
NY Times had an article a couple years ago about it being the last affordable ski resort. With the number of Colorado plates we are seeing that seems to be true. Prime time lift ticket is $79 compared to $200 in CO
We were there one summer when The Boss went to Philmont for cub scoutmaster training and I tagged along as supercargo . What a beautiful area. Especially the drive from Philmont to Anglefire. At almost 8,400 feet I understand the airport there is not for the faint of heart.
Crosswinds make it quite dangerous. Just had a plane go down this fall taking off when the winds were 50 mph. Fellow had been a commercial pilot. Should have known better.
The runway was extended to 8000’ in the 80s by a fellow named Lassiter (sp) so he could ferry coke up from S Am. Got caught by the feds and was later pardoned by Bill Clinton
This discussion of vacuum advance takes me back to when I first got my car, '66 S1. It was not running very well, cutting out/missing at 2500-3500+ rpm and generally unhappy as it would rev up under throttle. Turned out the main culprit was a spark plug lead that was off the plug, but close enough for the spark to jump at lower rpms and run ok, but falter at the higher rpms.
However, I also discovered the timing @ 750 rpm was at 0, using a timing light. I advanced the dynamic timing to the 10 BTDC spec for a 9:1 compression ratio @ 750 rpm (I’m quite certain I found that in a service manual). The difference was dramatic between finding the plug wire issue and resetting the timing. This cat wanted to fly. However, the PO, who is an acquaintance and had had the car serviced by a knowledgeable mechanic, vehemently warned me that I would burn up the engine. Did I take off the vacuum line when setting, was convinced I had not. So, I double checked.
With the vacuum line off unplugged, off and plugged, or on, all gave me the same timing of 10 BTDC. The vacuum line was having no effect at 750 rpm. The vacuum port is stock, in front (carb side) of the butterfly, not on the intake manifold side. The vacuum line is securely connected to the distributor. The distributor is a Pertronix electronic point distributor w/vac adv from Cool Cat (I have the invoice).
So, the discussion above identifies the advantage of vacuum advance under light load conditions, cruising and idling. I seem to have nothing at idle as there is no vacuum. Is this discussion saying the vacuum123 can add advance at idle where our mechanical systems don’t, and what would be the vacuum source? The car ran great all summer/fall.
So Phil, if your engine “wants” more advance at part throttle, light loads…at a particular rpm…
Why not do it with springs and weights?
When one dips into the throttle - the vacuum adv. reduces does it not? Albeit slowly.
So how did V.A. benefit the situation, beyond what a properly spec’d mechanical adv. would deliver?
Doing it with springs and weights gives you only two one-dimensional workspace:- the advance varies by known fixed amounts according to revs and by different fixed amounts dictated by vacuum.
By contrast, the 123 (or any other mapped ignition) allows you alter the advance differently in that two dimensional matrix space, e.g. the low to high rpm centrifugal advance need not be the same profile at low vacuum load as it is at high vacuum load - you can tailor the advance to the engine’s needs and tune out anomolies which do not persist all of the way through the rev range or all of the way through the vacuum range.
So, my question then is, is it beneficial to run our vacuum advance from a manifold source rather than a ported source so we get advance at idle on top of the 10 BTDC spec? It’d be easy enough to do. Would the standard vacuum advance unit in the car designed to run off the ported vacuum provide the correct amount of advance with full vacuum occurring at idle in the manifold?
From the article…
“Ported Vacuum” was strictly an early pre-converter crude emissions strategy and nothing more. Don’t believe anyone who tells you that ported vacuum is a good thing for performance and drivability – it’s not. Anyone with a street-driven car without manifold-connected vacuum advance is sacrificing idle cooling, throttle response, engine efficiency, and fuel economy, probably because they don’t understand what vacuum advance is, how it works, and what it’s for.
An example. A 1965 Cessna 172 has a takeoff roll of almost double at a pressure altitude of 6,000 feet at 30C compared to sea level at 15C. Angle Fire has that long runway for a very good reason.
Humidity also plays a role. As humidity goes up air pressure goes down so lift goes down. Probably not an issue at Angle Fire though.
No, your engine was designed to work with ported vacuum. The Corvette article is hopelessly muddled. Let me clear this up: all pre-emissions vacuum advance distributors used ported vacuum. If you say different, show me. The Corvette guy is sadly confused, probably because there was a period where many cars had BOTH ported and manifold vacuum. Manifold vacuum was used to control emissions during closed throttle deceleration, while ported vacuum was used in normal idle conditions for better driveability. A vacuum switching valve was added to control which vacuum source was applied based on engine load. The reason for this is that closing a carb throttle under elevated RPM enriches the mixture, and the extra advance gives it more time to burn. The best explanation can be found here:
And the source article he refers to is a Chrysler Master Tech publication, and is the most authoritative, contemporary article I’ve seen on early emissions control technology. Here’s a corrected link:
I’m interested in a few of the things that have been said here about the 123 distributor:
I can see where the distributor could be smart enough to “simulate” ported vacuum. But not without a vacuum signal. In other words, if it had a manifold vacuum signal, then “no additional advance at idle” is just another dot on the map. But if there’s no load signal, I don’t see how it could simulate anything with regard to vacuum advance.
It was implied above that it senses combustion efficiency and makes adjustments on a cylinder by cylinder basis. Is this true? The only system I’ve ever heard of that did that was SAAB Trionic, which somehow measured coil secondary current to detect the ionization rate in the cylinders.
Michael, I am not sure where I read this, I am not sure how true it is, and I am not sure if it is relevant (enough disclamers ) But I understand some of the newer ignitions can compensate and adjust ignition timing based on the “expected” crank position. In other words, if a spark is fired at crank position A, the crank sensor expects to see the crank at position B at time C. If the crank is not at that position as expected, the controller will assume something is not quite correct, and will make adjustments so the crank does reach that expected position at the correct time.
Tom
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
58
This can result in an unstable idle. But, perhaps more importantly to the car market, it gets old trying to tell people that they must disconnect the vacuum prior to adjusting the timing. With the vacuum line connected to a ported source, you don’t really need to disconnect it to set the timing.
This confirms your dissy is connected to “Ported vacuum” (as opposed to direct manifold vacuum). Vacuum is only presented to the dissy vacuum advance module once the throttle is opened by about ±5%. My views on ported vs manifold vacuum is summarized here: Ported vs Manifold vacuum
Yes. The vacuum123 can add advance at idle, but so can the good old mechanical dissies. Simply change the source of vacuum to a point directly exposed to manifold vacuum. (This is what I do on all my classic cars - reasons as per my views Ported vs Manifold vacuum)
This discussion and others seem to agree on the merits of having vacuum advance under light load conditions, but the debate is raging unabated on the merits of having vacuum advance applied AT IDLE.
Because your dissy is fed with ported vacuum, your engine (and you) are not getting the benefits of vacuum advance at idle.
As Marek says, you don’t have the control and flexibility that you have with electronic mapping. Having said that, I regard the good old dissy with points and weights and vacuum advance that our forefathers conceived, with the same degree of respect that awe that I have for what they achieved with carbs like the SU, ZS and Carter Thermoquad (Holley specifically excluded).
Correct
Not correct. The change in vacuum is applied for all intents and purposes, instantaneously to the vacuum advance module which responds at an “equal” rate. Vacuum advance changes are as rapid as they occur based on throttle and rpm changes (high frequency, sub second rpm and vacuum changes excluded.)
My answer to this question is well described in this thread (and that Corvette article): Ported vs Manifold vacuum
My view is ABSOLUTELY YES!!! There are however many that can not see/accept the reasons why.
The VA module applies x advance for y vacuum - regardless of rpms. So the vacuum it gets will be applied and will most likely result in full advance. Is this amount of advance “Correct” as in “optimal”? Most likely not. Is it better than having no advance at all? I contend that it is MUCH better to have full advance at idle rather than none. Like I said, IDLE is ALSO a part throttle condition. It just happens to exist at idle speed.
I agree with that article 100%.
The 123 BT version can be programmed with the “optimal” amounts of vacuum advance at idle, if measured on an engine dyno. I don’t have an engine dyno, so I simply find the least amount of vacuum advance that will yield max idle revs.
See!! There you have it. Again Frank, the question that should be asked is: WHY was the engine designed to work with ported vacuum??
In my view the Corvette guy is not confused. I’m sure glad to find 1 other individual in the world who shares my views and who is willing to take a stand on the matter.
Correct. The 123 is best utilised with manifold vacuum applied. You can then simulate ported vacuum simply by removing any vacuum advance at idle rpm. (And then suffer the consequences…)
That statement also intrigued me. I do know that the 123 offers intelligent variable coil charge time (dwell), that results in a spark during cranking (low battery volts) that is just as strong as during idle or at 6000rpm full throttle.
It is rather the other way round Tom. The controller knows at all times where the crank is, its current rotation speed and how fast it is accelerating or decelerating and can thus calculate the exact moment a spark should be applied for a given amount of spark advance.
Both my Jensen Interceptors, my S3 E-type, XJS, DD6, Chev C10 are running on manifold vacuum. I have yet to experience this alleged idle instability. My firend’s 4.2 S1 with the 123BT dissy also idles with vacuum advance applied.
Correct.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
60
Just for fun, I’ll point out that the V12 H.E. has a very complicated scheme to apply partial vacuum at idle! It involves a vacuum regulator. There is a signal from a ported vacuum source that switches the vacuum regulator from applying a fixed 11" of vacuum to applying full manifold vacuum.
As I said before, the problem with applying full vacuum at idle is that you can get an unstable idle. The engine gets into a cycle involving the manifold vacuum going up and down as the idle fluctuates. That’s why most systems use ported vacuum, and it’s why the H.E. uses that vacuum regulator. However, I can easily see an all-electronic dizzy having a scheme by which an unstable idle isn’t an issue. One way is to have a fixed amount of advance everywhere under 1000 rpm. So with such a dizzy, having the vacuum line connected to intake manifold can work fine.
) But I understand some of the newer ignitions can compensate and adjust ignition timing based on the “expected” crank position. In other words, if a spark is fired at crank position A, the crank sensor expects to see the crank at position B at time C. If the crank is not at that position as expected, the controller will assume something is not quite correct, and will make adjustments so the crank does reach that expected position at the correct time.